Gold as a Sensing Platform for the Rapid Detection of Explosives and Malarial Biomarkers

Abstract

Gold’s resistance to oxidation and exhibition of unique chemical and physical properties enable the development of current sensor and diagnostic platforms. This dissertation elucidates novel sensor platforms for the rapid detection of explosives and malarial biomarkers, respectively, by exploiting the catalytic and chromogenic properties of nanoscale gold. Initially, bulk gold serves as a substrate to biomimetically recognize explosive small molecules with peptide ligands at the cost of sensitivity. To enhance detection, immobilized gold nanoparticles electrocatalytically facilitate explosive molecule detection in a size-dependent manner. Taking advantage of gold’s optical properties, a colorimetric proof-of-concept assay amenable to the developing world is presented by capturing a malarial protein biomarker, inducing a red-to-purple color change and overcoming many obstacles associated with low-resource diagnostics. To increase biomarker sensitivity, gold-plated polystyrene microspheres mimic the phenomenon elicited by coffee rings to capture and concentrate the protein, allowing for the rapid interpretation of results and providing a simple user interface.